Purpose:

The purpose of this SAE Aerospace Information Report (AIR) is to provide the aerospace propulsion industry with recommended assembly torque limits for commonly used aircraft propulsion system threaded fasteners when a common torque value per size is the objective.

Field of Application:

To supply information on recommended torque limits for tension type nuts and bolts of the following materials and plating combinations given in Table 1.

For bolt and nut materials and the plating combinations in Table 1, the following conditions prevail:

a. Threads and bearing surface are lubricated with MIL-PFR-7808 aircraft engine oil.

b. Torque to be applied to the nut, whenever possible. Where torque is applied to the bolt head, no binding should occur between bolt shank and clearance hole, and under the bolt head that would affect the torque-induced preload.

c. For the specific bolt and nut material and plating combinations, the average coefficient of friction is assumed to be as indicated in Table 1.

d. The minimum tensile yield strength at room temperature of bolt and nut is as indicated in Table 1.